Commute Route - Columbia, MD to DC

Has or does anyone commute from the Columbia/Elkridge, MD area into downtown DC? If so, could you recommend a route? Been looking into it and seems there is little to no trail coverage and lots of busy (ie, dangerous) surface streets. Thanks.

I've never commuted to DC, but I've ridden my bike for fun from Severn (very near BWI Airport) to downtown DC. There were some trail portions (the Northwest Branch section of the Anacostia Tributary Trails http://bikewashington.org/trails/branches/nw-branch.htm, and some of the new Metropolitan Branch Trail is now open, too http://www.metbranchtrail.com, although it wasn't available when I last rode to DC), but, yes, by and large you are on the road. It didn't strike me as particularly dangerous, but (i) I'm accustomed to riding in traffic, and (ii) this wasn't during a weekday rush hour.

For any interested, I managed to roughly plot a route based on some of the info shared here. A little longer than I expected, but considering the driving distance, it's not too bad. Here's a link to the map: http://www.gmap-pedometer.com/?r=4501839. Thanks again to those who responded. It helped.